Aviation of World War II

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Po-2NAK U-2 as a night artillery spotter
  • Night Artillery Spotter
  • Polikarpov

U-2NAK (night artillery spotter) . Released by plant number 51 on the basis of the serial U-2VS (LNB) by retrofitting it according to the model approved by the State Research Institute of the Air Force KA dated 20.10.43.

The aircraft was intended to perform night adjustment of artillery fire and night artillery reconnaissance.

The additional equipment of the aircraft included:

a) installation:

- RSI-4 transmitting and receiving radio station (RSI-4 receiver on the instrument panel of the second cockpit; RSI-3 transmitter initially in the hatch on the right side of the fuselage immediately behind the second cockpit, then, according to the test results, on the continuation of the floor directly behind the seat of the second cabin, while the side bag was removed, and the attachment of the soft seat back was made on two belts with buckles);

- generator GS-350M in the collapse between 1 and 2 cylinders of the engine with a belt drive from the crankshaft of the engine, the regulator box RK-12 f-350 and the filter box KF-10-350 (both in front on the firewall on the right under the hood of the sub-engine installation);

- aircraft intercom SPU-F-2;

- four UV irradiation fittings (two in each cabin) to illuminate the scales of aircraft devices and luminous stencils;

- cockpit lighting that allowed the pilot and letnab to work with the map;

- annular exhaust manifold equipped with MAKF-4 flame arresters and silencers;

b) replacing the starting magneto with a KP-4716 type starting coil and installing an AFP type ignition filter and a K-4 type motor start button;

c) rearrangement of instruments on the dashboard of the second cockpit in connection with the installation of the RSI-4 receiver;

d) metallization of fuselage units, hand and foot control of the aircraft;

e) additional installation of the electrical network caused by additional equipment of the aircraft.

Military tests of five aircraft of this type were carried out from June 10 to July 28, 1944 in the 118 separate corrective and reconnaissance aviation regiment 2 VA 1 of the Ukrainian Front, about 100 km east of Lvov. Combat work was carried out from the Zarubishche jump airfield and from the landing site near the village of Staro-Alekseevka. The aircraft fully met its purpose and successfully passed the tests, despite the loss of all prototypes. However, these were not combat losses.

The first U-2NAK was lost on the night of June 28. When approaching the target, the crew lost their bearings and had to land. At the same time, when landing in the Dubno area, the plane burned down from the explosion of lighting bombs, which were not dropped by the crew due to forgetfulness.

The second U-2NAK was crashed on the night of July 8 during a training flight, also due to loss of orientation by the crew. The third prototype was destroyed on a forced landing on July 23, again due to the crew's loss of orientation during the return from a combat mission.

In the process of military tests, minor inconveniences and minor defects in the aircraft equipment were revealed. As the most advantageous for adjusting the artillery fire, the recommended heights were 1000-1500 m at a distance of up to 40 km from the receiving radio station, for night reconnaissance - 600-1000 m, which provided a preview of the reconnaissance object even without the SAB lighting.

The aircraft was serially built and widely used in the last period of the war.

Radio station RSI-4 at U-2 NAK

U-2GN ("Voice of Heaven"). Produced by plant number 51 in 1944 on the basis of U-2VS (leading the aircraft from OKB B.N.Fadeev, production of plant number 494 in Kozlovka on the Volga). The aircraft was intended to conduct agitation and propaganda among enemy troops at night. For these purposes, armament was removed from the U-2VS serial aircraft built at plant No. 464 and additional equipment was carried out:

- set of sound broadcasting station of SGU-43 type is installed;

- an electric power supply is installed - a GS-1000 generator with a belt drive from the motor shaft on a propeller similar to U-2NAK and a regulating box RK-32-1000;

- installed 3-color signaling for communication between aircraft crew members;

- the observer pilot's instrument panel was rearranged, caused by the installation of the SGU-43 control panel;

- additional installation of the electrical network, caused by the installation of SGU-43, was performed.

The set of the SGU-43 sound broadcasting station included: a 200 GRED-3 loudspeaker, an amplifier, a power panel, a control panel, RUK-300 and RUNZOA umformers, installation cables.

The loudspeaker was mounted in the aircraft fuselage behind the second cockpit, with the horn down. A hole was made in the lower plane of the fuselage along the inner contour of the horn.

The amplifier was mounted on the cockpit floor in front of the control pedals near the firewall. To cool the amplifier, air was used, which entered through a special fitting on the left side, and then, accordingly, was released into the atmosphere.

The control panel was installed in the letnab's cockpit on the dashboard depreciation part directly along the aircraft axis. As a result, the usual instruments on the board were rearranged. To the left of the flap, a compass and a speed indicator were installed, to the right - an altitude indicator and a clock. A pocket for a correction table was attached under the flap. The ignition toggle switches have been moved from the shock-absorbing part of the board to the left side of the main dashboard.

The power shield was installed on the starboard side of the letnab's cockpit.

Umformers RUK-300 and RUN-ZOA were located on the floor of the second cabin, respectively, to the right and left of the seat.

U-2GN was produced in duplicate and was successfully used at the front.

Photo Description
Drawing Po-2NAK

Drawing Po-2NAK


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